class Solution
{
public:
    int search(vector<int> &nums, int target)
    {
        int l = 0, r = nums.size() - 1;
        while (l <= r)
        {
            int mid = (l + r) >> 1;
            if (nums[mid] < target)
                l = mid + 1;
            else if (nums[mid] > target)
                r = mid - 1;
            else
                return mid;
        }
        return -1;
    }
};